Real Risk of Arrest for Marijuana Possession: "It is also important to point out that in no Western country is a user at much risk of being criminally penalized for using marijuana. The rates of arrest for past-year marijuana users in Western countries are typically less than or equal to 3 percent (Kilmer, 2002; Room et al., 2010). More important, almost none of those convicted of simple possession is incarcerated or receives a fine exceeding $1,000 (Pacula, MacCoun, et al., 2005)."
Treatment Admissions for Marijuana in the US, 1992-2002, and Referrals from the Criminal Justice System: "A recent issue of The DASIS Report2 examined marijuana treatment admissions between 1992 and 2002 and found that between these years [1992 and 2002] the rate of substance abuse treatment admissions reporting marijuana as their primary substance of abuse3 per 100,000 population increased 162 percent.
Political History of Marijuana Law Reform: "The identification of cannabis as a potentially dangerous psychoactive substance did not, however, prevent a substantial number of these enquiries to explore the issue of whether current legislation reflected the real dangers posed by cannabis. Already in 1944, the La Guardia Committee Report on Marihuana concluded that ‘the practice of smoking marihuana does not lead to addiction in the medical sense of the word’ and that ‘the use of marihuana does not lead to morphine or heroin or cocaine addiction’ (Zimmer and Morgan, 1997).
Cannabis and Diagnoses of Schizophrenia and Psychoses: "In terms of the model set out in the Introduction, the expected rise in diagnoses of schizophrenia and psychoses did not occur over a 10 year period. This study does not therefore support the specific causal link between cannabis use and the incidence of psychotic disorders based on the 3 assumptions described in the Introduction.
Public Health Impact of Marijuana Use: "The public health burden of cannabis use is probably modest compared with that of alcohol, tobacco, and other illicit drugs. A recent Australian study96 estimated that cannabis use caused 0·2% of total disease burden in Australia—a country with one of the highest reported rates of cannabis use. Cannabis accounted for 10% of the burden attributable to all illicit drugs (including heroin, cocaine, and amphetamines).
Cannabis and Psychosis: "Although individual lifetime risk of chronic psychotic disorders such as schizophrenia, even in people who use cannabis regularly, is likely to be low (less than 3%), cannabis use can be expected to have a substantial effect on psychotic disorders at a population level because exposure to this drug is so common."
Marijuana Decriminalization and Prevalence of Use: "Proponents of criminalization attribute to their preferred drug-control regime a special power to affect user behavior. Our findings cast doubt on such attributions. Despite widespread lawful availability of cannabis in Amsterdam, there were no differences between the 2 cities [Amsterdam and San Francisco] in age at onset of use, age at first regular use, or age at the start of maximum use."
"Our findings do not support claims that criminalization reduces cannabis use and that decriminalization increases cannabis use."
Decriminalization and Use Rates: "The available evidence suggests that removal of the prohibition against possession itself (decriminalization) does not increase cannabis use. In addition to the Dutch experience from 1976 to 1983, we have similar findings from analysis of weaker decriminalization (with fines retained for the offense of simple possession of small quantities) in 12 US states (Single, 1989) and South Australia and the Australian Capital Territory (Hall, 1997; McGeorge & Aitken, 1997).
"In California and Ohio, surveys before and after decriminalisation showed that cannabis use increased, but not at a greater rate than in US states which had not decriminalised cannabis. Single (1989) also reviewed data from two large US national surveys of drug use in the 1970s that compared rates of cannabis use in states which had and had not decriminalised cannabis. He found that the prevalence of cannabis use increased in all states, with a larger increase in those states which had not decriminalised (Single, 1989)."
Primary Cultivation States: "California, Hawaii, Kentucky, Oregon, Tennessee, Washington, and West Virginia are the primary marijuana cultivation states (M7 states). Domestic Cannabis Eradication/Suppression Program (DCE/SP) data show that more than 8 million plants were eradicated in 2008, 89 percent (7,136,133 plants of 8,013,308 plants) of which were eradicated in the M7 States."